Author : Madhan Kumar Kantha Samy
Publisher :
ISBN 13 :
Total Pages : 124 pages
Book Rating : 4.:/5 (181 download)
Book Synopsis Field Test and Analysis of Two Prestressed Concrete Bridges After Deck Replacement with Frp Panels by : Madhan Kumar Kantha Samy
Download or read book Field Test and Analysis of Two Prestressed Concrete Bridges After Deck Replacement with Frp Panels written by Madhan Kumar Kantha Samy and published by . This book was released on 2007 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridges B-0071 and B-0171 in Hamilton County, Ohio have been in service for about fifty years. They are short span bridges with prestressed concrete girders. Until late 2001, they had conventional reinforced concrete decks, which have been replaced with fiber reinforced polymer (FRP) decks. Two girders in bridge B-0171 were replaced with new prestressed girders. These bridges are significant as there are few instances of FRP decks on concrete girders. The Hamilton County Engineers Office contracted with the Civil Engineering Department at the University of Cincinnati to perform load testing on the bridges. Information gained from this research will seek to confirm the safety of the new technology, evaluate construction and design techniques with reference to the FRP deck, and determine overall performance of the bridge to provide understanding of the system. The two short span prestressed concrete bridges with fiber reinforced polymer decks were subjected to four sets of nondestructive truckload testing. Strain gauges were placed along the height of the girder cross-section, and longitudinally and transversely across the bottom of the deck. Displacement transducers were placed to measure overall girder displacement, relative deck displacement, deck panel separation, and deck-girder connection separation. A three-dimensional finite element analysis model was created to replicate the performance of each bridge. The two new prestressed girders in bridge B-0171 strengthened the bridge considerably and increased its load carrying capacity. But the old prestressed girders in bridge B-0071 and bridge B-0171 did not show any sign of deterioration. The four sets of test data collected over a two-year period show that the age effect on structural behavior is very small for both the bridges. The deck had very little influence on the distribution of loads in the structure for these bridges. Due to low deck stiffness and incomplete connectivity, the FRP deck did little to strengthen the girders. The long term monitoring of the deck result complied with the short term testing as reported by Eder8. The finite element model closely matched with the structural components of the original bridge. The new improved model is a better representation as it was calibrated with four sets of field data collected over a period of two years. The field test data from both tests shows that the girders are simply supported on the abutment. But the girders in the model are designed as fixed end beams to have a reasonable value for the modulus of concrete used in the model. In reality it can be assumed that the support condition is between fixed and simply supported. It was also demonstrated that the deck had very little influence on the distribution of loads in the structure for these bridges. The majority of the load transfer between girders was most likely due to the diaphragms. The Impact Factor based on one set of experimental results was 1.217. However, for analysis the LRFD value of 1.33 was used. The Load Rating Factor for bridge B-0071 was 1.66 and for bridge B-0171 was 2.48 with the governing truck loading being the Design load Type Tandem. These rating factors were based on girder performance only due to insufficient deck information.
